1. Field
The present invention relates to an artificial nipple which is used, for example, at the time when an infant or the like is given the breast and/or an infant feeding device, and also relates to an artificial nipple manufacturing method.
2. Description of Conventional Art
An infant at an age for ingesting the milk of its mother may ingest not only the mother's milk but also the squeezed milk or artificially prepared milk. For this ingestion, an infant feeding bottle can be utilized for containing that prepared milk or the like.
This infant feeding bottle is provided with an artificial nipple for performing roles similar to those of the mother's nipple.
This artificial nipple is formed of silicone rubber or isoprene rubber into a hollow structure having a space formed therein for retaining a passage for the prepared milk.
On the other hand, the mother's nipple does not have a hollow structure but rather includes solid tissue.
It is known that the infant performs, when it ingests the mother's milk or the prepared milk, a tongue peristalsis motion, in which its tongue is waved in abutment against the nipple or the like.
This tongue peristalsis motion is described in the following. At first, the infant envelops the mother's nipple with its own tongue to bring the tip of the mother's nipple into a recess called the “infant feeding cavity” in its own mouth.
Next, as the infant stimulates the mother's nipple or the like with its tongue to promote the secretion of the mother's milk and to move the milk to the tip of the nipple, the infant's tongue begins to bulge from its leading end side so that the tongue bulge continuously moves toward the root side. This tongue motion is called the “tongue peristalsis motion”.
By this movement or the tongue peristalsis motion of the bulge from the tongue leading end, the nipple is deformed and extended. Moreover, the nipple tip is formed from solid tissue, so that it is extended, while being slightly deformed and crushed, toward the leading end side.
Specifically, the infant moves its tongue bulge to suck the mother's milk to the leading side of the nipple. In the mouth, the closed space is formed by the nipple tip, the tongue bulge, the infant feeding cavity, the soft roof of mouth and so on.
This closed space is formed to increase its volume by the motion of the tongue so that it is evacuated to establish a negative pressure by the tongue motion. The nipple has its tip sucked into the closed space evacuated, so that the nipple is further deformed.
Next, the mother's milk thus secreted by the stimulation by the tongue peristalsis motion or by the accompanying negative pressure flows into the mouth of the infant. Then, the infant brings its tongue out of contact with the soft mouth roof thereby to open the closed space, and swallows the mother's milk. Thus, the infant ingests the mother's milk or the like.
The peristalsis motion by the infant's tongue is thus far described. However, the artificial nipple is hollow inside, but the mother's nipple is solid inside. Thus, when the infant performs this tongue peristalsis motion on the artificial nipple and the mother's nipple, these nipples are differently deformed.
When the infant performs the ingestion of the mother's milk by the mother's nipple and the ingestion of the prepared milk by the artificial nipple in parallel, the deformations of the nipples by the individual tongue peristalsis motions are different. As a result, the baby is confused in the peristalsis motions, and may receive the phenomenon called the “mammary papilla confusion”, in which the baby cannot ingest the mother's milk well.
This phenomenon called the “mammary papilla confusion” is caused due to the aforementioned structural difference between the mother's nipple and the artificial nipple. In order to eliminate this difference, therefore, there have been proposed various artificial nipples, e.g., Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4 and Patent Document 5, where Patent Document 1: JP-A-2000-189496 (FIG. 1, etc.); Patent Document 2: JP-A-63-24948 (FIG. 1, etc.); Patent Document 3: JP-UM-B-36-15480 (Figure, etc.); Patent Document 4: JP-UM-B-4-41864 (FIG. 1, etc.); and Patent Document 5: JP-UM-B-36-29265 (Figure, etc.).